CDE-1 suppresses the production of risiRNA by coupling polyuridylation and degradation of rRNA

• Published in: BMC biology 2020-09, Vol.18 (1), p.115-115, Article 115
• Main Authors: Wang, Yun, Weng, Chenchun, Chen, Xiangyang, Zhou, Xufei, Huang, Xinya, Yan, Yonghong, Zhu, Chengming
• Format: Article
• Language: English
• Subjects: Animals; Argonaute; Caenorhabditis elegans - genetics; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - metabolism; CDE-1; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cytoplasm; Degradation; Gene Silencing; Germ Cells - metabolism; Heredity; Immune system; Immunoprecipitation; Mass spectrometry; Mass spectroscopy; Proteins; risiRNA; RNA; RNA Interference; RNA modification; RNA polymerase; RNA, Helminth - metabolism; RNA, Ribosomal - metabolism; RNA, Small Interfering - metabolism; RNA-mediated interference; rRNA; siRNA; Stem cells; SUSI-1; Transposons; Tumorigenesis; Uridine - metabolism; Viruses; Young adults
• ISSN: 1741-7007; 1741-7007
• DOI: 10.1186/s12915-020-00850-z

Modification of RNAs, particularly at the terminals, is critical for various essential cell processes; for example, uridylation is implicated in tumorigenesis, proliferation, stem cell maintenance, and immune defense against viruses and retrotransposons. Ribosomal RNAs can be regulated by antisense ribosomal siRNAs (risiRNAs), which downregulate pre-rRNAs through the nuclear RNAi pathway in Caenorhabditis elegans. However, the biogenesis and regulation of risiRNAs remain obscure. Previously, we showed that 26S rRNAs are uridylated at the 3'-ends by an unknown terminal polyuridylation polymerase before the rRNAs are degraded by a 3' to 5' exoribonuclease SUSI-1(ceDIS3L2). Here, we found that CDE-1, one of the three C.elegans polyuridylation polymerases (PUPs), is specifically involved in suppressing risiRNA production. CDE-1 localizes to perinuclear granules in the germline and uridylates Argonaute-associated 22G-RNAs, 26S, and 5.8S rRNAs at the 3'-ends. Immunoprecipitation followed by mass spectrometry (IP-MS) revealed that CDE-1 interacts with SUSI-1(ceDIS3L2). Consistent with these results, both CDE-1 and SUSI-1(ceDIS3L2) are required for the inheritance of RNAi. This work identified a rRNA surveillance machinery of rRNAs that couples terminal polyuridylation and degradation.